/**
 _ _____           _          _     _
 | |  __ \         (_)        | |   | |
 ___ ___ | | |__) |___  ___ _ ______ _| |__ | | ___
 / __/ _ \| |  _  // _ \/ __| |_  / _` | '_ \| |/ _ \
 | (_| (_) | | | \ \  __/\__ \ |/ / (_| | |_) | |  __/
 \___\___/|_|_|  \_\___||___/_/___\__,_|_.__/|_|\___|

 v 1.5 - a jQuery plug-in by Alvaro Prieto Lauroba

 Licences: MIT & GPL
 Feel free to use or modify this plugin as far as my full name is kept

 If you are going to use this plug-in in production environments it is
 strongly recommended to use its minified version: colResizable.min.js

 */

(function ($) {

    var d = $(document); 		//window object
    var h = $("head");			//head object
    var drag = null;			//reference to the current grip that is being dragged
    var tables = [];			//array of the already processed tables (table.id as key)
    var count = 0;				//internal count to create unique IDs when needed.

    //common strings for packing
    var ID = "id";
    var PX = "px";
    var SIGNATURE = "JColResizer";
    var FLEX = "JCLRFlex";

    //short-cuts
    var I = parseInt;
    var M = Math;
    var ie = navigator.userAgent.indexOf('Trident/4.0') > 0;
    var S;
    try {
        S = sessionStorage;
    } catch (e) {
    }	//Firefox crashes when executed as local file system

    //append required CSS rules
    h.append("<style type='text/css'>  .JColResizer{/*table-layout:fixed;*/} .JColResizer td, .JColResizer th{overflow:hidden;padding-left:0!important; padding-right:0!important;}  .JCLRgrips{ height:0px; position:relative;} .JCLRgrip{margin-left:-5px; position:absolute; z-index:5; } .JCLRgrip .JColResizer{position:absolute;background-color:red;filter:alpha(opacity=1);opacity:0;width:10px;height:100%;cursor: e-resize;top:0px} .JCLRLastGrip{position:absolute; width:1px; } .JCLRgripDrag{ border-left:1px dotted black;	} .JCLRFlex{width:auto!important;}</style>");


    /**
     * Function to allow column resizing for table objects. It is the starting point to apply the plugin.
     * @param {DOM node} tb - reference to the DOM table object to be enhanced
     * @param {Object} options    - some customization values
     */
    var init = function (tb, options) {
        var t = $(tb);										//the table object is wrapped
        t.opt = options;
        if (t.opt.disable) return destroy(t);				//the user is asking to destroy a previously colResized table
        var id = t.id = t.attr(ID) || SIGNATURE + count++;	//its id is obtained, if null new one is generated
        t.p = t.opt.postbackSafe; 							//short-cut to detect postback safe
        if (!t.is("table") || tables[id] && !t.opt.partialRefresh) return; 		//if the object is not a table or if it was already processed then it is ignored.
        t.addClass(SIGNATURE).attr(ID, id).before('<div class="JCLRgrips"/>');	//the grips container object is added. Signature class forces table rendering in fixed-layout mode to prevent column's min-width
        t.g = [];
        t.c = [];
        t.w = t.width();
        t.gc = t.prev();
        t.f = t.opt.fixed;	//t.c and t.g are arrays of columns and grips respectively
        if (options.marginLeft) t.gc.css("marginLeft", options.marginLeft);  	//if the table contains margins, it must be specified
        if (options.marginRight) t.gc.css("marginRight", options.marginRight);  	//since there is no (direct) way to obtain margin values in its original units (%, em, ...)
        t.cs = I(ie ? tb.cellSpacing || tb.currentStyle.borderSpacing : t.css('border-spacing')) || 2;	//table cellspacing (not even jQuery is fully cross-browser)
        t.b = I(ie ? tb.border || tb.currentStyle.borderLeftWidth : t.css('border-left-width')) || 1;	//outer border width (again cross-browser issues)
        // if(!(tb.style.width || tb.width)) t.width(t.width()); //I am not an IE fan at all, but it is a pity that only IE has the currentStyle attribute working as expected. For this reason I can not check easily if the table has an explicit width or if it is rendered as "auto"
        tables[id] = t; 	//the table object is stored using its id as key
        createGrips(t);		//grips are created

    };


    /**
     * This function allows to remove any enhancements performed by this plugin on a previously processed table.
     * @param {jQuery ref} t - table object
     */
    var destroy = function (t) {
        var id = t.attr(ID), t = tables[id];		//its table object is found
        if (!t || !t.is("table")) return;			//if none, then it wasn't processed
        t.removeClass(SIGNATURE + " " + FLEX).gc.remove();	//class and grips are removed
        delete tables[id];						//clean up data
    };


    /**
     * Function to create all the grips associated with the table given by parameters
     * @param {jQuery ref} t - table object
     */
    var createGrips = function (t) {

        var th = t.find(">thead>tr>th,>thead>tr>td");	//if table headers are specified in its semantically correct tag, are obtained
        if (!th.length) th = t.find(">tbody>tr:first>th,>tr:first>th,>tbody>tr:first>td, >tr:first>td");	 //but headers can also be included in different ways
        th = th.filter(":visible");					//filter invisible columns
        t.cg = t.find("col"); 						//a table can also contain a colgroup with col elements
        t.ln = th.length;							//table length is stored
        if (t.p && S && S[t.id]) memento(t, th);		//if 'postbackSafe' is enabled and there is data for the current table, its coloumn layout is restored
        th.each(function (i) {						//iterate through the table column headers
            var c = $(this); 						//jquery wrap for the current column
            var g = $(t.gc.append('<div class="JCLRgrip"></div>')[0].lastChild); //add the visual node to be used as grip
            g.append(t.opt.gripInnerHtml).append('<div class="' + SIGNATURE + '"></div>');
            if (i == t.ln - 1) {
                g.addClass("JCLRLastGrip");
                if (t.f) g.html("");
            }
            g.bind('touchstart mousedown', onGripMouseDown); //bind the mousedown event to start dragging 

            g.t = t;
            g.i = i;
            g.c = c;
            c.w = c.width();		//some values are stored in the grip's node data
            t.g.push(g);
            t.c.push(c);						//the current grip and column are added to its table object
            c.width(c.w).removeAttr("width");				//the width of the column is converted into pixel-based measurements
            g.data(SIGNATURE, {i: i, t: t.attr(ID), last: i == t.ln - 1});	 //grip index and its table name are stored in the HTML
        });
        t.cg.removeAttr("width");	//remove the width attribute from elements in the colgroup
        syncGrips(t); 				//the grips are positioned according to the current table layout
        //there is a small problem, some cells in the table could contain dimension values interfering with the
        //width value set by this plugin. Those values are removed
        t.find('td, th').not(th).not('table th, table td').each(function () {
            $(this).removeAttr('width');	//the width attribute is removed from all table cells which are not nested in other tables and dont belong to the header
        });
        if (!t.f) {
            t.removeAttr('width').addClass(FLEX); //if not fixed, let the table grow as needed
        }


    };


    /**
     * Function to allow the persistence of columns dimensions after a browser postback. It is based in
     * the HTML5 sessionStorage object, which can be emulated for older browsers using sessionstorage.js
     * @param {jQuery ref} t - table object
     * @param {jQuery ref} th - reference to the first row elements (only set in deserialization)
     */
    var memento = function (t, th) {
        var w, m = 0, i = 0, aux = [], tw;
        if (th) {										//in deserialization mode (after a postback)
            t.cg.removeAttr("width");
            if (t.opt.flush) {
                S[t.id] = "";
                return;
            } 	//if flush is activated, stored data is removed
            w = S[t.id].split(";");					//column widths is obtained
            tw = w[t.ln + 1];
            if (!t.f && tw) t.width(tw);			//it not fixed and table width data available its size is restored
            for (; i < t.ln; i++) {						//for each column
                aux.push(100 * w[i] / w[t.ln] + "%"); 	//width is stored in an array since it will be required again a couple of lines ahead
                th.eq(i).css("width", aux[i]); 	//each column width in % is restored
            }
            for (i = 0; i < t.ln; i++)
                t.cg.eq(i).css("width", aux[i]);	//this code is required in order to create an inline CSS rule with higher precedence than an existing CSS class in the "col" elements
        } else {							//in serialization mode (after resizing a column)
            S[t.id] = "";				//clean up previous data
            for (; i < t.c.length; i++) {	//iterate through columns
                w = t.c[i].width();		//width is obtained
                S[t.id] += w + ";";		//width is appended to the sessionStorage object using ID as key
                m += w;					//carriage is updated to obtain the full size used by columns
            }
            S[t.id] += m;							//the last item of the serialized string is the table's active area (width),
            //to be able to obtain % width value of each columns while deserializing
            if (!t.f) S[t.id] += ";" + t.width(); 	//if not fixed, table width is stored
        }
    };


    /**
     * Function that places each grip in the correct position according to the current table layout
     * @param {jQuery ref} t - table object
     */
    var syncGrips = function (t) {
        t.gc.width(t.w);			//the grip's container width is updated
        for (var i = 0; i < t.ln; i++) {	//for each column
            var c = t.c[i];
            t.g[i].css({			//height and position of the grip is updated according to the table layout
                left: c.offset().left - t.offset().left + c.outerWidth(false) + t.cs / 2 + PX,
                height: t.opt.headerOnly ? t.c[0].outerHeight(true) : t.outerHeight(true)
            });
        }
    };


    /**
     * This function updates column's width according to the horizontal position increment of the grip being
     * dragged. The function can be called while dragging if liveDragging is enabled and also from the onGripDragOver
     * event handler to synchronize grip's position with their related columns.
     * @param {jQuery ref} t - table object
     * @param {number} i - index of the grip being dragged
     * @param {bool} isOver - to identify when the function is being called from the onGripDragOver event
     */
    var syncCols = function (t, i, isOver) {
        var inc = drag.x - drag.l, c = t.c[i], c2 = t.c[i + 1];
        var w = c.w + inc;
        var w2 = c2.w - inc;	//their new width is obtained
        c.width(w + PX);
        t.cg.eq(i).width(w + PX);
        if (t.f) { //if fixed mode
            c2.width(w2 + PX);
            t.cg.eq(i + 1).width(w2 + PX);
        }
        if (isOver) {
            c.w = w;
            c2.w = t.f ? w2 : c2.w;
        }
    };


    /**
     * This function updates all columns width according to its real width. It must be taken into account that the
     * sum of all columns can exceed the table width in some cases (if fixed is set to false and table has some kind
     * of max-width).
     * @param {jQuery ref} t - table object
     */
    var applyBounds = function (t) {
        var w = $.map(t.c, function (c) {			//obtain real widths
            return c.width();
        });
        t.width(t.width()).removeClass(FLEX);	//prevent table width changes
        $.each(t.c, function (i, c) {
            c.width(w[i]).w = w[i];				//set column widths applying bounds (table's max-width)
        });
        t.addClass(FLEX);						//allow table width changes
    };


    /**
     * Event handler used while dragging a grip. It checks if the next grip's position is valid and updates it.
     * @param {event} e - mousemove event binded to the window object
     */
    var onGripDrag = function (e) {
        if (!drag) return;
        var t = drag.t;		//table object reference 
        var oe = e.originalEvent.touches;
        var ox = oe ? oe[0].pageX : e.pageX;    //original position (touch or mouse)
        var x = ox - drag.ox + drag.l;	        //next position according to horizontal mouse position increment
        var mw = t.opt.minWidth, i = drag.i;	//cell's min width
        var l = t.cs * 1.5 + mw + t.b;
        var last = i == t.ln - 1;                 			//check if it is the last column's grip (usually hidden)
        var min = i ? t.g[i - 1].position().left + t.cs + mw : l;	//min position according to the contiguous cells
        var max = t.f ? 	//fixed mode?
            i == t.ln - 1 ?
                t.w - l :
                t.g[i + 1].position().left - t.cs - mw :
            Infinity; 								//max position according to the contiguous cells
        x = M.max(min, M.min(max, x));				//apply bounding
        drag.x = x;
        drag.css("left", x + PX); 	//apply position increment
        if (last) {									//if it is the last grip
            var c = t.c[drag.i];					//width of the last column is obtained
            drag.w = c.w + x - drag.l;
        }
        if (t.opt.liveDrag) { 			//if liveDrag is enabled
            if (last) {
                c.width(drag.w);
                t.w = t.width();
            } else {
                syncCols(t, i); 			//columns are synchronized
            }
            syncGrips(t);
            var cb = t.opt.onDrag;							//check if there is an onDrag callback
            if (cb) {
                e.currentTarget = t[0];
                cb(e);
            }		//if any, it is fired
        }
        return false; 	//prevent text selection while dragging
    };


    /**
     * Event handler fired when the dragging is over, updating table layout
     */
    var onGripDragOver = function (e) {

        d.unbind('touchend.' + SIGNATURE + ' mouseup.' + SIGNATURE).unbind('touchmove.' + SIGNATURE + ' mousemove.' + SIGNATURE);
        $("head :last-child").remove(); 				//remove the dragging cursor style
        if (!drag) return;
        drag.removeClass(drag.t.opt.draggingClass);		//remove the grip's dragging css-class
        var t = drag.t;
        var cb = t.opt.onResize; 	    //get some values
        var i = drag.i;                 //column index
        var last = i == t.ln - 1;         //check if it is the last column's grip (usually hidden)
        var c = t.g[i].c;               //the column being dragged
        if (last) {
            c.width(drag.w);
            c.w = drag.w;
        } else {
            syncCols(t, i, true);	//the columns are updated
        }
        if (!t.f) applyBounds(t);	//if not fixed mode, then apply bounds to obtain real width values
        syncGrips(t);				//the grips are updated
        if (cb) {
            e.currentTarget = t[0];
            cb(e);
        }	//if there is a callback function, it is fired
        if (t.p && S) memento(t); 						//if postbackSafe is enabled and there is sessionStorage support, the new layout is serialized and stored
        drag = null;									//since the grip's dragging is over
    };


    /**
     * Event handler fired when the grip's dragging is about to start. Its main goal is to set up events
     * and store some values used while dragging.
     * @param {event} e - grip's mousedown event
     */
    var onGripMouseDown = function (e) {
        var o = $(this).data(SIGNATURE);			//retrieve grip's data
        var t = tables[o.t], g = t.g[o.i];			//shortcuts for the table and grip objects
        var oe = e.originalEvent.touches;           //touch or mouse event?
        g.ox = oe ? oe[0].pageX : e.pageX;            //the initial position is kept
        g.l = g.position().left;
        d.bind('touchmove.' + SIGNATURE + ' mousemove.' + SIGNATURE, onGripDrag).bind('touchend.' + SIGNATURE + ' mouseup.' + SIGNATURE, onGripDragOver);	//mousemove and mouseup events are bound
        h.append("<style type='text/css'>*{cursor:" + t.opt.dragCursor + "!important}</style>"); 	//change the mouse cursor
        g.addClass(t.opt.draggingClass); 	//add the dragging class (to allow some visual feedback)
        drag = g;							//the current grip is stored as the current dragging object
        if (t.c[o.i].l) for (var i = 0, c; i < t.ln; i++) {
            c = t.c[i];
            c.l = false;
            c.w = c.width();
        } 	//if the colum is locked (after browser resize), then c.w must be updated
        return false; 	//prevent text selection
    };


    /**
     * Event handler fired when the browser is resized. The main purpose of this function is to update
     * table layout according to the browser's size synchronizing related grips
     */
    var onResize = function () {
        for (t in tables) {
            var t = tables[t], i, mw = 0;
            t.removeClass(SIGNATURE);						//firefox doesn't like layout-fixed in some cases
            if (t.f && t.w != t.width()) {					//if the the table's width has changed and it is in fixed mode
                t.w = t.width();							//its new value is kept the active cells area is obtained
                for (i = 0; i < t.ln; i++) mw += t.c[i].w;
                //cell rendering is not as trivial as it might seem, and it is slightly different for
                //each browser. In the beginning i had a big switch for each browser, but since the code
                //was extremely ugly now I use a different approach with several re-flows. This works
                //pretty well but it's a bit slower. For now, lets keep things simple...
                for (i = 0; i < t.ln; i++) t.c[i].css("width", M.round(1000 * t.c[i].w / mw) / 10 + "%").l = true;
                //c.l locks the column, telling us that its c.w is outdated
            }
            syncGrips(t.addClass(SIGNATURE));
        }

    };


    //bind resize event, to update grips position
    $(window).bind('resize.' + SIGNATURE, onResize);


    /**
     * The plugin is added to the jQuery library
     * @param {Object} options -  an object that holds some basic customization values
     */
    $.fn.extend({
        colResizable: function (options) {
            var defaults = {

                //attributes:
                draggingClass: 'JCLRgripDrag',	//css-class used when a grip is being dragged (for visual feedback purposes)
                gripInnerHtml: '',				//if it is required to use a custom grip it can be done using some custom HTML
                liveDrag: false,				//enables table-layout updating while dragging
                fixed: true,                    //table width does not change if columns are resized
                minWidth: 15, 					//minimum width value in pixels allowed for a column
                headerOnly: false,				//specifies that the size of the the column resizing anchors will be bounded to the size of the first row
                hoverCursor: "e-resize",  		//cursor to be used on grip hover
                dragCursor: "e-resize",  		//cursor to be used while dragging
                postbackSafe: false, 			//when it is enabled, table layout can persist after postback or page refresh. It requires browsers with sessionStorage support (it can be emulated with sessionStorage.js).
                flush: false, 					//when postbakSafe is enabled, and it is required to prevent layout restoration after postback, 'flush' will remove its associated layout data
                marginLeft: null,				//in case the table contains any margins, colResizable needs to know the values used, e.g. "10%", "15em", "5px" ...
                marginRight: null, 				//in case the table contains any margins, colResizable needs to know the values used, e.g. "10%", "15em", "5px" ...
                disable: false,					//disables all the enhancements performed in a previously colResized table
                partialRefresh: false,			//can be used in combination with postbackSafe when the table is inside of an updatePanel

                //events:
                onDrag: null, 					//callback function to be fired during the column resizing process if liveDrag is enabled
                onResize: null					//callback function fired when the dragging process is over
            }
            var options = $.extend(defaults, options);
            return this.each(function () {
                init(this, options);
            });
        }
    });
})(jQuery);